I have been running musket/firestaff with light armor in pvp primarily since i hit 60 and spent alot of gold trying to get it to a point where i would not drag down my team in OPR. And while its not the most powerful build out there, its actually alot of fun once you get your priorities straight.
I dont use the musket on heavies unless i just want to add the powderburn dot to help other dps kill the target, or there are no other better targets.
Snipe out archers, mages, other musket users or healers. Even if you dont kill them, smashing enough damage and a powder burn into them will make them have to reposition and burn their healing pot.
Heavy healers though, they are more or less a lost cause with the current patch.
You are most likely gonna be a straight up glass cannon to squeeze enough damage out of your musket to be efficient, so if anything gets close to you, you straight up bail and reposition.
If you happen to find yourself forced in to close quarters, lets say, you are trying to cap one of the bases in OPR and you need to stay on point, just pull out the firestaff instead. Most of the people in the cap zone are gonna be heavies, so trying to snipe out a heavy in that situation is just a detriment to your team.
In fact, dont get to hung up on the musket, there are plenty of situations where swapping out to the firestaff is better. Heck, maybe it would pair up well with a ice gauntlet? I just like the bail out option burn out gives you.
For me the musket is more about stacking empower buffs, and hitting my shots consistently, my third shot on a target is normally the hardest, so i dont recommend building the musket as a first hit big, one shot, big number, kind of weapon.
But thats just what works for me, someone smarter and more experienced has probably cooked up a better build than i ever could.
Use a honing stone, and get damage buff food if you are running OPR. You are gonna need the damage boost to get big numbers on lights and medium, and if the stars align you might smash some big numbers into a heavy as well.
BUT, this is all for PVP, the pve part of the musket is mediocre at best from my experience. The only place where i have found the musket to be somewhat efficient when it comes to pve is in invasions, sticky bomb for big groups, shooters stance to help take out the siege engines, dropping marksmen, and the suicide bombers. But even then, i mostly use the firestaff.
The thing i want changed the most for muskets are honestly the crosshair, and having shots that actually hit in the center of the crosshairs instead of slightly left of the center.
I hear they did something on PTR to make the reload time less torturous, so i am really looking forward to that.
Cant say anything about the bow, never gave it much of my time.